This experimental study demonstrates a novel optical method which is used as a readout system for a vertical seismometer that is, based on the moiré technique. Our purpose was to build an optical seismometer whose performance is similar to seismic sensors. The oscillation system of the sensor is a spring-suspended mass which its position is monitored by moiré technique. The maximum displacement is limited by mechanical issues to a few millimeters. We used two similar overlaid grids at a small angle that, one of them is fixed to the frame of the sensor and the other one is attached to the suspended mass. Moiré pattern is illuminated with a laser diode. The laser beam passes through the moiré pattern and a narrow slit and hits on a light detector. Due to moving the oscillatory mass and the fringes movements, the light intensity on the detector varies and is recorded as voltage. A digital signal processor samples the output voltage and produces a record of the seismometer mass displacement. The response of the optical seismometer was validated through comparison of recorded waveforms with those obtained by CMG-6TD seismometer. Comparisons with conventional seismometer show that, in terms of both noise and signal fidelity, the optical approach is quite viable. Our seismometer was found to be compatible with the reference seismometer.
Chen, X. and Yu, S. (2013) Optical inertial vibration sensor system using grating technology. Optical Engineering, 52(7), 077104. doi:10.1117/1.oe.52.7.077104
Stein, S. and Wysession, M. (2003) An Introduction to Seismology, Earthquakes, and Earth Structure. Blackwell Publishing, Oxford. 3. Ben-Menahem, A. (2009) Historical Encyclopedia of Natural and Mathematical Sciences. Springer, ISBN 9783540688310. Retrieved 28.
Sleeswyk, A.W. and Sivin, N. (1983) Dragons and toads: the Chinese seismoscope of BC. 132. Chinese Science, 6, 1-19.
Borgstrom, S., De Lucia, M., and Nave, R. (1999) Luigi Palmieri: first scientific bases for geophysical surveillance in Mt. Vesuvius area. Annali Di Geofisica , 42(3), DOI: 10.4401/ag-3741.
Herbert-Gustar, A.L. and Nott, P.A. (1980) John Milne: Father of Modern Seismology. Tenterden: Paul Norbury. ISBN 9780904404340, OCLC 476242679.
IEEE (2011) 175 years of electrical detection and warning of natural disasters. IEEE History Center, Issue 86, 3-4.
Zumberge, M., Berger, J., Otero, J., and Wielandt, E. (2010) An optical seismometer without force feedback. Bulletin of the Seismological Society of America, 100(2), 598-605.
Acernese, F., Rosa, R.D., Garufi, F., Romano, R., and Barone, F. (2006) A Michelson interferometer for seismic wave measurement: theoretical analysis and system performances. Remote Sensing for Environmental Monitoring, GIS Applications, and Geology VI. doi:10.1117/12.687907.
Aaltonen, L., Rahikkala, P., Saukoski, M., and Halonen, K. (2009) High-resolution continuoustime interface for micromachined capacitive accelerometer. International Journal of Circuit Theory and Applications, 37(2), 333-349.
Levinzon, F.A. (2004) Fundamental noise limit of piezoelectric accelerometer. IEEE Sens. J., 4(1), 108-111.
Rodgers, P.W. (1993) Maximizing the signalto-noise ratio of the electromagnetic seismometer: the optimum coil resistance, amplifier characteristics, and circuit. Bulletin of the Seismological Society of America , 83(2), 561-582.
Liu, Y., Fan, K., Chu, C., Werner, C.A., and Jager, G. (2008) Development of an optical accelerometer for low-frequency vibration using the voice coil on a DVD pickup head. Measurement Science and Technology, 19(8), 084012. doi:10.1088/0957-0233/19/8/084012.
Basumallick, N., Chatterjee, I., Biswas, P., Dasgupta, K., and Bandyopadhyay, S. (2012) Fiber Bragg grating accelerometer with enhanced sensitivity. Sensors and Actuators A: Physical, 173(1), 108-115.
Gangopadhyay, T.K. (2004) Prospects for fiber Bragg gratings and Fabry-Perot interferometers in fiber optic vibration sensing. Sensors and Actuators A: Physical, 113(1), 20-38.
Kamenev, O.T. Petrov, Y.S., and Khizhnyak, R.V. (2012) Optoelectronic Seismograph on the Basis of a Mach-Zehnder Interferometer. Pacific Science Review, 14(1), 28-29.
Lebanon, G. and Bruckstein, A.M. (2001) Variational approach to moire pattern synthesis. Journal of the Optical Society of America A, 18(6), 1371.
Ragulskis, M. Saunoriene, L., and Maskeliunas, R. (2009) The structure of Moire grating lines and its influence to time-averaged fringes. Experimental Techniques, 33(2), 60-64.
Rasouli, S. Tavassoly, M.T. (2006) Application of Moire technique to the measurement of the atmospheric turbulence parameters related to the angle of arrival fluctuations. Optics Letters, 31(22), 3276-3278.
Rasouli, S., Madanipour, K., and Tavassoly, M.T. (2006) Measurement of modulation transfer function of the atmosphere in the surface layer by Moire technique. Optics in Atmospheric Propagation and Adaptive Systems IX, doi:10.1117/12.687614.
Ragulskis, M. and Navickas, Z. (2009) Time Average Geometric Moire-Back to the Basics. Experimental Mechanics, 49(4) 439-450.
Ragulskis, M. (2009) Time-Averaged Patterns Produced by Stochastic Moire Gratings. Computers and Graphics, 33(2), 147-150.
Esmaeili, Sh., Rasouli, S., and Soubouti, F. (2010) Design and construction of a seismometer based on the Moire technique. Annual Physics Conference of Iran, physics society of Iran, Hamedan, 62-65.
Rasouli, S., Esmaeili, Sh., and Sobouti, F. (2011) A quantitative investigation of the Moire seismometer. 17th Optics Photonic Conference, Optics and Photonics Society of Iran, Kerman, 20-24.
Amidror, I. (2000) The Theory of Moire Phenomenon. Kluwer Academic Publishers, Netherlands.
Esmaeili, Sh., Ansari, A., and Hamzehloo, H. (2015) A New Optical Method for Detecting Seismic Vibrations. 7th Conference of Seismology and Earthquake Engineering, Tehran, Iran.
Esmaeili, Sh., Rasouli, S., Sobouti, F., and Esmaeili, S. (2012) A Moire micro strain gauge (MMSG). Optics Communications, 285(9), 2243-2246, doi:10.1016/j.optcom.2011.12.006.
Gupta, H.R., Mehra, R. (2013) Power spectrum estimation using Welch method for various window techniques. International Journal of Scientific Research Engineering and Technology (IJSRET), 2(6), 389-392.
Esmaeili, S., Ansari, A., & Hamzehloo, H. (2016). An Optical Approach for Sensing Seismic Vibrations. Journal of Seismology and Earthquake Engineering, 18(2), 91-100.
MLA
Shamseddin Esmaeili; Anooshiravan Ansari; Hossein Hamzehloo. "An Optical Approach for Sensing Seismic Vibrations". Journal of Seismology and Earthquake Engineering, 18, 2, 2016, 91-100.
HARVARD
Esmaeili, S., Ansari, A., Hamzehloo, H. (2016). 'An Optical Approach for Sensing Seismic Vibrations', Journal of Seismology and Earthquake Engineering, 18(2), pp. 91-100.
VANCOUVER
Esmaeili, S., Ansari, A., Hamzehloo, H. An Optical Approach for Sensing Seismic Vibrations. Journal of Seismology and Earthquake Engineering, 2016; 18(2): 91-100.
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